Prognostic Impact of TEL–AML-1 Fusion Gene on Acute Lymphoblastic Leukemia

The TEL–AML-1 fusion gene resulting from 12: 21 chromosomal translocation is believed to be the most common molecular genetic abnormality in childhood acute lymphoblastic leukemia (ALL). This study was conducted to investigate the frequency of this fusion gene in children suffering from ALL attending the oncology unit in the Basrah Hospital for Pediatric and Gynecology during the period May 2009 to April 2010, and point out the different laboratory features associated with this anomaly.
A total of 120 blood samples were collected (60 early-diagnosed ALL children and 60 healthy children as control group). The controls were matched with cases by age and sex. Ribonucleic acid (RNA) was successfully extracted from the fresh blood of 40 ALL cases used for the detection of TEL–AML-1 fusion gene by reverse transcriptase–polymerase chain reaction (RT-PCR).
Of the newly diagnosed ALL cases, 27.5% were positive for TEL–AML-1 fusion gene as well as 5% among the control group. All TEL–AML-1 positive cases showed an age peak between 3 and 6 years and tend to occur more frequently among females than males. The TEL–AML-1 positive cases were classified as the standard-risk group and accounted for 72.3%, while 27.3% were the high-risk group (P < 0.05). According to the French-American–British classification criteria, 72.3% of the high-risk and 68% of the standard-risk groups belong to the L2 stage.
The TEL–AML-1 fusion gene identifies a subset of pediatric ALL associated with a number of laboratory markers of good prognosis and should thus be considered in routine molecular work of ALL to confirm its impact on clinical outcome and to design a suitable therapy.